1974 F100 302 2WD 180+K

I've been told the 87 octane is what I need to use and that the premium 93 won't do me any good exept drain my wallet faster.

Are there ANY advantages / disadvantages to changing my single for a dual exhaust on this vehicle or is this (like the gas issue) a waste of money and time?

Looks like the time is quickly coming to have to replace /repair some of the exhaust system and want to hear opinions on this before moving forward. Thanks.

Jim

 

J,
They were right and they were wrong. If your timing is advanced, say up to 36 degrees, high octane gas will save your bacon. High octane gas is the cure to prevent preignition.
Secondly, dual exhaust is the number one performance improver for the 302. A set of headers and a couple of 2-1/2" pipes back to 45 degree turns in front of the rear tires. For the money vs. the preformance returned, nothing compares.
KingFisher

 

Dual Exhaust!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

Definitely true dual exhaust.

 

I am not having any pinging or knocking so I think my timing is still on (isn't pinging a symptom of preignition?) -- Thanks to all so far.

2 1/2 in. pipes the "best" for me?

Jim

 

J,
If your timing is set for a total advance of, say, 18 degrees, it will make no difference what type of gas you run. but if, your timing is set at 34 degrees total advance, 87 octane will ping and 93 won't.
Gabish?
KingFisher
PS Your car will run faster at 34 degrees total advance.

 

KingFisher, Capito, and thanks!

Jim

 

Your timing requirements are determined by your cam and compression ratio and just plain engine characteristics, flame spread patterns etc. Your fuel requirements are set by the same parameters. Upping the timing will not make you any more HP or go faster, but if you need higher octane fuel to compensate for it your wallet will get lighter faster.

A dual exhaust will sound different but the main restriction to your exhaust is the exhaust manifolds.

 

Eric,
You are simply wrong. Advancing your timing will make more horsepower! It's that simple. Advancing it too far will destroy your motor. That's pretty simple to. I understand that we have a responsibility not to mislead those seeking knowledge. Those individuals must realize that the explanations forwarded here are never complete and as thorough as to be taken at face. Advancing your timing may require that you richen your air/fuel ratio or lower your thermostat temp. or replace your radiator with a larger one. Or you may simply advance your distributor a few degrees and get away with it. If you hear it "PING" you know you went too far. As you start to play with your motor, you'll learn more about it.
Good Luck to the curious,
KingFisher

 

I will stand by my original statement.

Optimum timing is set by the above mentioned factors. The factory timing may not be set to optimum because of emissions and fuel mileage considerations.

Playing with the A/F ratio may allow you to move the timing a few degrees. Doing so may actually lower your fuel mileage and possibly HP. Good old tradeoffs. Lowering your thermostat temp on these old beasts will increase engine wear and decrease your fuel mileage. Replacing your radiator will have very little effect if any if everything else is as it should be.

 

Okay, I realize I am taking this thread on a slight digression, but how does lowering the tstat temp INCREASE wear? I'm not trying to be a snot here.....edjumicate me....I just put a lower tstat in my truck this summer, and have noticed:
1) more power, runs smoother, feels stronger
2) better oil pressure readings (on my aftermarket manual gauge). I would often drop to about 7 PSI, and now it rarely drops below 15
3) no change in oil consumption (which for all practical purposes, it doesn't)

4) I have experienced a drop in fuel mileage, but I think that is more due to reason #1

My tranny, well on its way to taking a long dirt nap, seems to be happier with the cooler temps as well, which is buying me more time to remedy its woes.

I kinda figured a lower t-stat temp would be just what the doctor ordered.

**I love a sound of a full throttle dual exhaust 460 in the morning.......it sounds like.....VICTORY!!**

 

Use the search function with "engine wear" and "thermostat" to find your answers.

One excellent thread is here: https://www.ford-trucks.com/forums/s...252Bthermostat This thread is referencing a performance add on product but a lot of info on thermostats is in it.

A good example of temperature based wear patterns can be found in a 6 cylinder engine where the front cylinder(s) often has more wear than the others due to the coolant circulation pattern.

 

Back to JStan's question "2 1/2 in. pipes the "best" for me? "

Many years ago, I had 2 1/2" duals put in my 79 F-150 w/ stock 302 2 bbl auto w/ 185K miles. I was getting prepped for my 429 and the short time I ran the 302 w/ those duals, I felt it was too large. It had much less bottom end torque and was revving much higher (which the stock cam,intake, etc., wasn't designed to do).

If you are leaving your 302 stock and not wanting it to run at higher rpms, you should be very happy w/ a good set of 2 1/4" duals.

I say this because I put that same tired 302 into an 83 Ranger w/ a set of 2 1/4" duals and flowmasters and it not only sounded like a Mustang, it performed great up to about 4500 or 5000. That was what that engine was designed to do w/ the stock cam, etc. Also, the gearing in the stock Ranger rear was lower than the F-150 so it was extremely quick up to about 85 mph, and then the engine was maxed out in stock setup.

I have also known some Buick guys that put 3" single exhaust into their GSX 3.1 L turbo cars and they sounded great, had plenty of bottom end and still breathed well enough to race.

Your stock single exhaust on that truck was/is probably 2 1/8", so imagine the difference in either a single 3" or dual 2 1/4".

 

I have found in my truck that the way to go with exhaust is duels to a duel inlet, single outlet muffler and a big tailpipe. My 79 F-250 S/C C/S 2wd 351M, C6, Dana 61. i went with 2 1/2" to the muffler and then a 3" tailpipe, all custom bends, nothing past 22 1/2 degree. It has lots more bottom end, and it sounds good too.
There is nothing like the sound of true duels, but in this part of the world there seems to be a lot of moisture, and they just rot. This system will last forever!!!
Good Luck

 

I always run 89 or better in my truck, it seems to get better mileage and performance. When I put 87 in, it just seems to drink it like it's nothing, the power doesn't really suffer much. My truck loves 93 octane! More punch and better mileage.